Check abstract method signatures coming from traits

Zend/tests/traits/abstract_method_1.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Abstract method from trait enforced in class
+--FILE--
+<?php
+
+trait T {
+    abstract public function neededByTheTrait(int $a, string $b);
+}
+
+class C {
+    use T;
+
+    public function neededByTheTrait(array $a, object $b) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Declaration of C::neededByTheTrait(array $a, object $b) must be compatible with T::neededByTheTrait(int $a, string $b) in %s on line %d

Zend/tests/traits/abstract_method_2.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Mutually incompatible methods from traits are fine as long as the final method is compatible
+--FILE--
+<?php
+
+trait T1 {
+    abstract public function test();
+}
+trait T2 {
+    abstract public function test(): int;
+}
+
+class C {
+    use T1, T2;
+
+    public function test(): int {}
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/traits/abstract_method_3.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Private abstract method from trait enforced in class
+--FILE--
+<?php
+
+trait T {
+    abstract private function neededByTheTrait(int $a, string $b);
+}
+
+class C {
+    use T;
+
+    private function neededByTheTrait(array $a, object $b) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Declaration of C::neededByTheTrait(array $a, object $b) must be compatible with T::neededByTheTrait(int $a, string $b) in %s on line %d

Zend/tests/traits/abstract_method_4.phpt

@@ -0,0 +1,20 @@
+--TEST--
+Visibility enforcement on abstract trait methods
+--FILE--
+<?php
+
+trait T {
+    abstract public function method(int $a, string $b);
+}
+
+class C {
+    use T;
+
+    /* For backwards-compatiblity reasons, visibility is not enforced here. */
+    private function method(int $a, string $b) {}
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/traits/abstract_method_5.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Staticness enforcement on abstract trait methods
+--FILE--
+<?php
+
+trait T {
+    abstract static public function method(int $a, string $b);
+}
+
+class C {
+    use T;
+
+    public function method(int $a, string $b) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot make static method T::method() non static in class C in %s on line %d

Zend/tests/traits/abstract_method_6.phpt

@@ -0,0 +1,20 @@
+--TEST--
+Abstract private trait method not implemented
+--FILE--
+<?php
+
+trait T {
+    abstract private function method(int $a, string $b);
+}
+
+abstract class C {
+    use T;
+}
+
+class D extends C {
+    private function method(int $a, string $b) {}
+}
+
+?>
+--EXPECTF--
+Fatal error: Class C must implement 1 abstract private method (C::method) in %s on line %d

Zend/tests/traits/abstract_method_7.phpt

@@ -0,0 +1,23 @@
+--TEST--
+Abstract private trait method forwarded as abstract protected method
+--FILE--
+<?php
+
+trait T {
+    abstract private function method(int $a, string $b);
+}
+
+abstract class C {
+    use T;
+
+    abstract protected function method(int $a, string $b);
+}
+
+class D extends C {
+    protected function method(int $a, string $b) {}
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/traits/bug60217b.phpt

@@ -22,4 +22,4 @@ class CBroken {
 $o = new CBroken;
 $o->foo(1);
 --EXPECTF--
-Fatal error: Declaration of TBroken1::foo($a) must be compatible with TBroken2::foo($a, $b = 0) in %s
+Fatal error: Declaration of CBroken::foo($a) must be compatible with TBroken2::foo($a, $b = 0) in %s on line %d

Zend/tests/traits/bug60217c.phpt

@@ -22,4 +22,4 @@ class CBroken {
 $o = new CBroken;
 $o->foo(1);
 --EXPECTF--
-Fatal error: Declaration of TBroken2::foo($a) must be compatible with TBroken1::foo($a, $b = 0) in %s on line %d
+Fatal error: Declaration of CBroken::foo($a) must be compatible with TBroken1::foo($a, $b = 0) in %s on line %d

Zend/zend_compile.c

@@ -6101,7 +6101,7 @@ void zend_begin_method_decl(zend_op_array *op_array, zend_string *name, zend_boo
 	}
 
 	if (op_array->fn_flags & ZEND_ACC_ABSTRACT) {
-		if (op_array->fn_flags & ZEND_ACC_PRIVATE) {
+		if ((op_array->fn_flags & ZEND_ACC_PRIVATE) && !(ce->ce_flags & ZEND_ACC_TRAIT)) {
 			zend_error_noreturn(E_COMPILE_ERROR, "%s function %s::%s() cannot be declared private",
 				in_interface ? "Interface" : "Abstract", ZSTR_VAL(ce->name), ZSTR_VAL(name));
 		}